JP6438925B2 - Cam chain guide structure of internal combustion engine - Google Patents

Description

  The present invention relates to a cam chain guide structure for an internal combustion engine that can prevent the cam chain from shaking.

A tensioner roller is provided between the driven sprocket of the camshaft and the drive sprocket of the crankshaft, and a cam chain tensioner device that presses the cam chain from the outer peripheral side and applies appropriate tension to the cam chain. In addition, a cam chain guide mechanism for an internal combustion engine provided with a sub guide roller that is guided by being sandwiched from the outer peripheral side, and a guide roller for guiding the cam chain on the inner peripheral side of the cam chain is provided between the driven sprocket and the tensioner roller. Conventionally, for example, it is shown by the following patent document 1.
In the one disclosed in Patent Document 1, the vibration of the cam chain between the guide roller and the sub guide roller can be effectively suppressed by the tension of the cam chain tensioner device. The cam chain may sway due to the difference in the width in the radial direction.

Japanese Patent No. 5009834 (FIGS. 2 to 4)

  The present invention has been made in view of the above prior art, and a guide roller is provided on the inner peripheral side of the cam chain between the driven sprocket and the drive sprocket, and the cam along with the sub guide roller is provided on the crankshaft side of the guide roller. An object of the present invention is to provide a cam chain guide mechanism capable of preventing the cam chain from swinging between a driven sprocket and a guide roller in a cam chain guide mechanism of an internal combustion engine having a tensioner roller that sandwiches the chain from the outer peripheral side. .

In order to solve the above problems, one aspect of the present invention is a driven sprocket that receives a rotational force from a crankshaft through an endless annular cam chain and rotates a camshaft supported by a cylinder head, and a cylinder block A guide roller that is pivotally supported by the cam chain and guides the cam chain on the inner peripheral side of the cam chain, and the cam chain is pressed from the outer peripheral side of the cam chain by a tensioner roller closer to the crankshaft side than the guide roller. In a cam chain guide structure for an internal combustion engine, comprising: a cam chain tensioner device that applies tension to the cam chain; and a sub guide roller that guides the cam chain so as to be sandwiched from the outer periphery side together with the tensioner roller.
The guide rollers Ri same diameter der and the driven sprocket, the guide at least part of the roller, the projects from the upper end surface of the cylinder block of an internal combustion engine, characterized in that positioned in the cylinder head cam chain guide Structure.
According to the above configuration, the driven sprocket and the guide roller have the same diameter, so that the cam chain travels between the driven sprocket and the guide roller on a virtual plane including the driven sprocket and perpendicular to the cam shaft. The movement of the cam chain in the vertical direction is reduced, and the cam chain can be prevented from shaking.
Further, the distance between the driven sprocket and the guide roller can be reduced to shorten the length of the cam chain, thereby suppressing the cam chain from shaking and contributing to a compact arrangement of the cylinder head and the cylinder block.
Further, according to the second aspect of the present invention, there is provided a driven sprocket that receives a rotational force from a crankshaft through an endless annular cam chain and rotates a camshaft supported by a cylinder head, and a cam sprocket supported by a cylinder block. A guide roller that guides the chain on the inner peripheral side of the cam chain, and a tensioner roller that presses the cam chain from the outer peripheral side of the cam chain on the crankshaft side of the guide roller to apply tension to the cam chain. In a cam chain guide structure of an internal combustion engine comprising a cam chain tensioner device and a sub guide roller that guides the cam chain so as to be sandwiched from the outer peripheral side together with the tensioner roller,
The guide roller has the same diameter as the driven sprocket,
From the upper end surface of the cylinder head to the lower end surface of the cylinder block, an axis center of the cam shaft and an axis center of the guide roller shaft of the guide roller in a side view of a cam chain chamber in which the cam chain is disposed. The cam chain guide structure for an internal combustion engine is characterized in that the front and rear surfaces with respect to the imaginary straight line are formed by surfaces that continue along the imaginary straight line direction.
According to the above configuration, the driven sprocket and the guide roller have the same diameter, so that the cam chain travels between the driven sprocket and the guide roller on a virtual plane including the driven sprocket and perpendicular to the cam shaft. The movement of the cam chain in the vertical direction is reduced, and the cam chain can be prevented from shaking.
In addition, the front and rear surfaces of the cam chain chamber with respect to a virtual straight line connecting the shaft center of the cam shaft and the shaft center of the guide roller shaft of the guide roller in a side view are configured to be continuous along the virtual straight line direction. In addition, since there are no discontinuous steps or gaps, the flow of oil flowing down the cam chain chamber is not hindered.

In the above configuration,
An inter-axis distance from the axial center of the cam shaft to the axial center of the guide roller axis of the guide roller, and an inter-axis distance from the axial center of the guide roller axis to the axial center of the sub guide roller axis of the sub guide roller May be equal.
According to the configuration, the inter-axis distance from the center of the cam shaft to the center of the guide roller shaft is made equal to the inter-axis distance from the center of the guide roller shaft to the center of the sub guide roller shaft. The extension of the cam chain between the driven sprocket and the guide roller and the extension of the cam chain between the guide roller and the sub guide roller can be made equal, and the deflection of the cam chain can be suppressed.

In the above configuration,
The cam chain tensioner device has an oil lock type tensioner lifter provided on a bearing wall of a crankcase and inserted and loaded with a push rod, and the tensioner roller is pivotally supported by a tensioner arm that is pressed and oscillated by the push rod. The crankcase is provided with an oil guide rib projecting from the bearing wall facing the cam chain chamber of the crankcase, and the lower end of the oil guide rib is in the cam chain chamber as viewed in the crankshaft direction. It extends to the upper part of the oil reservoir provided on the bearing wall facing the oil reservoir, and the oil lock tensioner lifter may be connected to the oil reservoir.
According to this configuration, an oil lock tensioner lifter into which a push rod is inserted and connected is connected to an oil reservoir provided in the bearing wall facing the cam chain chamber, and the bearing wall facing the cam chain chamber Oil is effectively supplied to the oil reservoir by the oil guide rib protruding from the end, so that the lack of oil in the oil lock tensioner lifter can be prevented, the function of the tensioner roller is ensured, and the cam by the guide roller Ensures the effect of suppressing chain swing.
In the above configuration,
The cam chain positioned forward and above the contact point with the guide roller with respect to the cam shaft, and the cam chain positioned rearward and above the contact point with the guide roller with respect to the cam shaft in a side view. And at least a part of the cam chain positioned forward and downward with respect to the guide roller and at least a part of the cam chain positioned rearward and downward with respect to the guide roller. In this case, they may be tilted in the direction in which the lower parts approach each other.
According to the configuration, the tension on the cam chain works reliably, and the suppression of the cam chain swing between the driven sprocket and the guide roller is more effectively exhibited .

According to the cam chain guide structure of one internal combustion engine of the present invention,
By making the driven sprocket and the guide roller have the same diameter, the cam chain perpendicular to the cam chain traveling direction between the driven sprocket and the guide roller on a virtual plane that includes the driven sprocket and is perpendicular to the camshaft. The movement becomes smaller and the cam chain can be prevented from shaking.
Further, the distance between the driven sprocket and the guide roller can be reduced to shorten the length of the cam chain, thereby suppressing the cam chain from shaking and contributing to a compact arrangement of the cylinder head and the cylinder block.
According to the cam chain guide structure of the second internal combustion engine of the present invention,
By making the driven sprocket and the guide roller have the same diameter, the cam chain perpendicular to the cam chain traveling direction between the driven sprocket and the guide roller on a virtual plane that includes the driven sprocket and is perpendicular to the camshaft. The movement becomes smaller and the cam chain can be prevented from shaking.
In addition, the front and rear surfaces of the cam chain chamber with respect to a virtual straight line connecting the shaft center of the cam shaft and the shaft center of the guide roller shaft of the guide roller in a side view are configured to be continuous along the virtual straight line direction. In addition, since there are no discontinuous steps or gaps, the flow of oil flowing down the cam chain chamber is not hindered.

1 is a left side view of a part of an internal combustion engine having a cam chain guide mechanism for an internal combustion engine according to an embodiment of the present invention, with a part being a cross section and a part of a rear part being omitted. FIG. 2 is a cross-sectional development view of the internal combustion engine taken generally in the direction of arrows II-II in FIG. It is sectional drawing which shows the structure of the cam chain tensioner apparatus by the III-III arrow in FIG.

A cam chain guide mechanism for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS.
The directions such as front, rear, left, right, up and down in the description and claims of the present specification are based on the direction of the vehicle when the internal combustion engine according to the embodiment is mounted on a vehicle (not shown) such as a motorcycle.
In the posture shown in FIG. 1, the left side in the figure is the front of the vehicle, the upper side in the figure is the upper side of the vehicle, the far side in the figure is the right side of the vehicle, and the front side in the figure is the left side of the vehicle.
In the figure, arrow FR indicates the front of the vehicle, LH indicates the left side of the vehicle, RH indicates the right side of the vehicle, and UP indicates the upper side of the vehicle.

FIG. 1 is a left side view of a part of an internal combustion engine 1 having a cam chain guide mechanism according to an embodiment of the present invention, with a part thereof being a cross section and a part of a rear part being omitted. The internal combustion engine 1 is an air-cooled single cylinder four-stroke cycle SOHC internal combustion engine.
The internal combustion engine 1 is mounted on a motorcycle with its crankshaft 21 oriented in the vehicle width direction of a motorcycle (not shown) that is a vehicle to be mounted, that is, in the left-right direction.
A transmission 3 is installed in the rear part of the crankcase 2 that rotatably supports the crankshaft 21, and the internal combustion engine 1 constitutes a so-called power unit.

  As shown in FIG. 1, a cylinder block 4 and a cylinder head 5 are sequentially stacked and fastened integrally on a diagonally upper side of the crankcase 2, and a cylinder head cover 6 is put on the cylinder head 5. The cylinder head 5 and the cylinder head cover 6 protrude from the crankcase 2 so as to be inclined forward slightly.

FIG. 2 is a developed cross-sectional view of the internal combustion engine 1 as viewed in the direction of arrows II-II in FIG.
As shown in FIG. 2, in the crankcase 2, the crankshaft 21 is rotatable in a left-right split manner via main bearings 23, 23 on the left bearing wall 22L of the left crankcase 2L and the right bearing wall 22R of the right crankcase 2R. Is pivotally supported.
The left and right crank webs 21w and 21w are positioned in the crank chamber 20 between the left and right bearing walls 22L and 22R, and the crankshaft 21 is coupled by a crank pin 21p, and the left and right bearing walls 22L and 22R. Left and right crankshaft portions 21L and 21R protrude from the left and right outer sides, and the left and right case covers 7L and 7R cover the outside.

In the crankcase 2, a main shaft 31 and a counter shaft 32 of the transmission 3 are rotatably supported in parallel with the crankshaft 21. The main shaft 31 and the counter shaft 32 are provided with a constantly meshing transmission gear group 30 g. It has been.
A shift clutch device 35 having a primary driven gear 34 is attached to the right end of the main shaft 31, and the primary driven gear 34 meshes with a primary drive gear 33 fitted to the right end of the right crankshaft portion 21R, and the crankshaft 21 Rotation is transmitted.

In accordance with the speed change operation, the speed change clutch device 35 is connected and disconnected, and the speed change mechanism of the speed change gear group 30g between the main shaft 31 and the counter shaft 32 is changed by a not-shown speed change mechanism to change the gear combination. Is done.
The rotation of the counter shaft 32 after the shift is transmitted from the output sprocket 36 fitted to the left end of the counter shaft 32 to the rear wheel of a motorcycle (not shown) that is a drive wheel via the drive chain 37.

A drive sprocket 59 of a valve drive system is fitted to the left crankshaft portion 21L in the vicinity of the main bearing 23.
On the other hand, a valve mechanism 50 is formed in the cylinder head 5 so that the cam shaft 51 is oriented parallel to the crankshaft 21, that is, in the vehicle width direction so as to be sandwiched by the cam shaft holder 52 on the upper surface of the cylinder head 5. A driven sprocket 53 that is pivotally supported and has a diameter twice that of the drive sprocket 59 of the valve drive system is fitted to the left end of the camshaft 51.

A cam chain 54, which is an endless annular transmission chain, is placed between a driven sprocket 53 fitted to the camshaft 51 and a drive sprocket 59 fitted to the crankshaft 21, so that the rotation of the crankshaft 21 is halved. And is transmitted to the camshaft 51.
Cam chain chambers 2c, 4c, and 5c that communicate with each other are formed on the left portions of the crankcase 2, the cylinder block 4, and the cylinder head 5, and the cam chain 54 passes through the cam chain chambers 2c, 4c, and 5c. It is arranged.

The cam chain chamber 2c of the crankcase 2 includes a left bearing wall 22L of the left crankcase 2L and an outer circumferential circular separator member 26 attached so as to close the circular opening 25 opened in the outer wall 2a on the left outer side. Formed between.
The separator member 26 is provided so as to partition the inside of the cam chain chamber 2c from the outside in the vehicle width direction.
In FIG. 1, the separator member 26 is removed and the circular opening 25 is released.

In the present embodiment, as shown in FIG. 1, the opening center 25 a of the circular opening 25 is provided at a position that is eccentric from the shaft center 21 a of the crankshaft 21.
Therefore, the distance from the shaft center 21a of the crankshaft 21 to the inner edge 25b of the circular opening 25 can be changed, and a member disposed on the inner side in the vehicle width direction from the circular opening 25, for example, a sub guide roller described later 56 does not need to be arranged within a certain range around the crankshaft 21, and the degree of freedom of layout in the crankcase 2 is improved.

The left crankshaft portion 21L penetrates the separator member 26 in an oil-tight manner, and an AC generator 10 is provided on the left end side thereof, and the AC generator 10 is covered with a left case cover 7L.
The separator member 26 is fastened to the boss 28 of the left bearing wall 22L by a mounting bolt 27, and the inner stator 10a of the AC generator 10 is attached to the outer surface. The outer rotor 10b of the AC generator 10 surrounding the inner stator 10a is the left crankshaft portion. It is attached to the left end of 21L

As shown in FIG. 1, a guide roller 55 having the same diameter as that of the driven sprocket 53 is rotatably supported in the cam chain chamber 4c of the cylinder block 4 (see FIG. 2). The cam chain 54 is guided so as to spread from the inner peripheral side to the outer peripheral side, and the rotation of the front side and the rear side of the cam chain 54 is guided.
In this embodiment, the guide roller 55 is pivotally supported by a guide roller shaft 57 that is screwed into the cam chain chamber 4c from the outer wall 4a of the cylinder block 4 (see FIG. 2).

  In the present specification and claims, the “same diameter” means the radial distance r53 from the rotation center 53c of the driven sprocket 53 to the pin center 54p of the cam chain 54 that is wound around and contacts the driven sprocket 53. And the radial distance r55 from the rotation center 55c of the guide roller 55 to the pin center 54p of the cam chain 54 that is pressed against and in contact with the guide roller 55 is equal, and is within the manufacturing error range.

  In FIG. 1, the crankshaft 21 rotates in the counterclockwise direction R. Therefore, the front side of the cam chain 54 spanned between the drive sprocket 59 and the driven sprocket 53 is directed downward by the drive sprocket 59. The rear side of the cam chain 54 is the side fed upward by the drive sprocket 59, that is, the “slack side”.

As shown in FIG. 1, in the cam chain chamber 2 c of the crankcase 2, a sub guide roller 56 is rotatably supported on the left bearing wall 22 </ b> L at a position obliquely above the front side of the drive sprocket 59, and the front side of the cam chain 54. Is positioned so as to be pushed in from the outer peripheral side.
As shown in FIG. 2, the sub guide roller 56 is pivotally supported on the outer periphery of one boss 28A of the bosses 28 protruding from the left bearing wall 22L for fastening the separator member 26. .
One boss 28A serves as the sub guide roller shaft 58 of the sub guide roller 56.

  As shown in FIG. 1, the inter-axis distance d1 from the shaft center 51a of the cam shaft 51 to the shaft center 57a of the guide roller shaft 57, and the shaft center of the sub-roller roller shaft 58 from the shaft center 57a of the guide roller shaft 57. The inter-axis distance d2 up to 58a is arranged to be equal.

Further, in the cam chain chamber 2c, a tensioner arm 80 of the cam chain tensioner device 8 is pivotally supported by a pivot bolt 81 at the rear of the drive sprocket 59 so as to be swingable.
A tensioner roller 82 is rotatably supported at the tip of the arm extending upward from the tensioner arm 80, and the rear end of the arm extending downward forms a contact end 80a.

The push rod 84 of the oil lock type tensioner lifter 83 is in contact with the contact end 80a of the tensioner arm 80 and presses and urges the tensioner roller 82 at the tip of the arm extending upward. The rear rotating part is pressed from the outer peripheral side.
Accordingly, the tensioner roller 82 of the cam chain tensioner device 8 presses the cam chain 54 from the outer peripheral side on the crankshaft 21 side with respect to the guide roller 55 so as to apply an appropriate tension to the cam chain 54.
Further, the sub guide roller 56 sandwiches the cam chain 54 from the outer peripheral side together with the tensioner roller 82 on the crankshaft 21 side from the guide roller 55, and guides the outer peripheral side of the cam chain 54.

The oil lock tensioner lifter 83 is formed below the drive sprocket 59 that is fitted to the crankshaft 21 that is pivotally supported by the left crankcase 2L.
FIG. 3 is a cross-sectional view showing the configuration of the cam chain tensioner device 8 as viewed in the direction of arrows III-III in FIG.
Hereinafter, referring to FIG. 1 and FIG. 3, the left bearing wall 22 </ b> L has a left bearing wall 22 </ b> L that passes through a portion of the peripheral wall 24 that extends leftward from the left bearing wall 22 </ b> L of the left crankcase 2 </ b> L. The guide hole 85 of the oil lock tensioner lifter 83 is perforated obliquely so that the lower portion outside the peripheral wall 24 is forward from the upper portion inside the peripheral wall 24, and penetrates the cam chain chamber 2c and the outside.

The upper part of the oil lock tensioner lifter 83 above the guide wall 85 of the guide hole 85 communicates with an oil reservoir 86 formed in the left bearing wall 22L, and the lower half of the guide hole 85 extends obliquely downward from the peripheral wall 24. The guide tube portion 87 is formed.
The oil sump portion 86 is a concave portion opened upward, and the left bearing wall 22L constitutes the right side wall, but the left side wall is missing, and instead, the side wall plate 88 is attached to the left side wall. Configure.
An upper opening of the guide hole 85 faces the oil reservoir 86. In other words, an oil lock tensioner lifter 83 is connected to the oil reservoir 86.

The push rod 84 of the oil lock type tensioner lifter 83 is inserted and loaded into the guide hole 85 from the upper opening and is slidably supported.
The push rod 84 is a cylindrical member having an outer diameter slightly smaller than the inner diameter of the guide hole 85, and a plurality of circular holes 84 a are formed at required positions on the cylindrical wall, and the push rod 36 passes through the circular hole 84 a from the oil reservoir 86. Oil can be supplied inside the cylinder.
A rubber head member 89 is fitted into the upper end opening of the push rod 84.
A control valve 90 is provided at the lower end opening of the push rod 84.

  In the control valve 90, a bottomed cylindrical valve seat 90a having a circular hole in the bottom wall is fitted slightly behind the lower end opening of the push rod 84, and a ball 90b is loosely fitted in the cylinder of the valve seat 90a. With a bottomed cylindrical valve cap 90c with a circular hole in the bottom wall applied to the opening of the valve seat 90a to prevent the ball 90b from falling, the ball 90c opens and closes to the circular hole of the valve seat 90a. It is configured to be possible.

A tensioner bolt 91 is screwed to the lower end of the guide tube portion 87 to close the lower end opening of the guide hole 85.
As described above, the push rod 84 having the control valve 90 at the lower end is inserted and loaded into the guide hole 85 from above, and the compression spring 92 is inserted into the guide hole 85 from below, so that the lower end opening of the guide hole 85 is attached to the tensioner bolt. When the plug is closed at 91, the push rod 84 is biased upward by the compression spring 92.

  The head member 89 at the upper end of the push rod 84 biased obliquely upward by the compression spring 92 abuts against the abutment end 80a of the tensioner arm 80, and the tensioner arm 80 and the pivot bolt 81 are Therefore, the tensioner roller 82 at the other end of the tensioner arm 80 presses the rear rotating portion of the cam chain 54 to apply a constant tension to the cam chain 54. be able to.

As described above, the oil accumulated in the oil reservoir 86 is supplied to the inside of the cylinder of the push rod 84 communicated via the circular hole 84a of the push rod 84, and further from the lower part inside the cylinder and further from the control valve 90. The oil chamber 85a which is the guide hole 85 in which the compression spring 92 is interposed is filled.
Accordingly, the push rod 84 is pushed by the tensioner arm 80, but the oil in the oil chamber 85a below the control valve 90 in the guide hole 85 presses the ball 90b against the circular hole of the valve seat 90a to close the valve. In this state, the push rod 84 is prohibited from moving backward (down).

When the cam chain 54 is loosened, the push rod 84 is moved forward by the urging force of the compression spring 92, and the tensioner arm 80 is swung to push the tensioner roller 82 deeply against the cam chain 54 to maintain the tension.
At this time, the control valve 90 opens and the oil in the push rod 84 enters the lower oil chamber 85a from the control valve 90, so that the push rod 84 can move forward.
The push rod 84 that has moved forward is prohibited from retreating by closing the control valve 90, and therefore, the cam chain 54 is not loosened again, and can be maintained by applying appropriate tension to the cam chain 54 at all times.

In the cam chain chamber 2c, an oil guide rib 29 inclined obliquely rearward and downward is provided below the sub guide roller 56 and the drive sprocket 59 so as to project leftward from the left bearing wall 22L of the crankcase 2.
The lower end of the oil guide rib 29 extends to above the oil reservoir (86) as viewed in the crankshaft direction. Oil or a left bearing that is dripped by the rotation of the drive sprocket 59 or the sub guide roller 56 and the rotation of the cam chain 54 The oil that flows down along the wall surface of the wall 22L on the cam chain chamber 2c side is received by the inclined oil guide rib 29 and guided downward, and the oil that has been guided by the oil guide rib 29 and flowed down from the lower end enters the oil reservoir 86. Since it is accepted, oil can be efficiently collected in the oil reservoir 86.

  As described above, in the internal combustion engine 1 of the present embodiment, the driven sprocket 53 that receives the rotational force from the crankshaft 21 via the endless annular cam chain 54 and rotates the camshaft 51, and the cam chain 54 are camped. A guide roller 55 that guides the inner side of the chain 54, and a cam chain tensioner device 8 that presses the cam chain 54 from the outer side by the tensioner roller 82 on the crankshaft 21 side of the guide roller 55 and applies tension to the cam chain 54. In addition, in the cam chain guide structure of the internal combustion engine 1 including the guide chain 56 that guides the cam chain 54 together with the tensioner roller 82 from the outer peripheral side, the guide roller 55 has the same diameter as the driven sprocket 53.

  Thus, by making the driven sprocket 53 and the guide roller 55 have the same diameter, the driven sprocket 53 and the guide roller 55 on the virtual plane P (see FIG. 2) that includes the driven sprocket 53 and is perpendicular to the cam shaft 51 The movement of the cam chain 54 in the direction perpendicular to the cam chain traveling direction is reduced, and the cam chain 54 can be prevented from shaking.

  Further, a distance d1 from the shaft center 51a of the cam shaft 51 to the shaft center 57a of the guide roller shaft 57 of the guide roller 55, and the shaft center of the sub guide roller shaft 58 of the sub guide roller 56 from the shaft center 57a of the guide roller shaft 57. Since the distance d2 to 58a is the same, the extension of the cam chain 54 between the driven sprocket 53 and the guide roller 55 and the extension of the cam chain 54 between the guide roller 55 and the sub guide roller 56 can be made equal. Uneven deflection of the chain 54 can be suppressed.

Also, by inserting the crankshaft 21 in the crankcase 2, with the outer peripheral circular separator member 26 which partitions the inside cam chain chamber 2c and the vehicle width direction outer side is provided, the crank case 2 the separator member 26 is attached The opening center 25 a of the circular opening 25 is provided at a position eccentric from the shaft center 21 a of the crankshaft 21.
Therefore, the distance from the shaft center 21a of the crankshaft 21 to the inner edge 25b of the circular opening 25 can be changed, and a member, for example, a sub guide roller 56 disposed on the inner side in the vehicle width direction than the circular opening 25 is provided. Therefore, it is not necessary to arrange the crankshaft 21 within a certain range around the crankshaft 21, and the degree of freedom of layout in the crankcase 2 is improved.

Also, a cam chain tensioner device 8 has an oil lock tensioner lifter 83 has been inserted loaded push rod 84 provided on the left bearing wall 22L of the crankcase 2, tensioner roller 82, the rocking is pressed by the push rod 84 It is pivotally supported by a moving tensioner arm 80.
The crankcase 2 is provided with an oil guide rib 29 projecting from the left bearing wall 22L facing the cam chain chamber 2c, and the lower end of the oil guide rib 29 is the left facing the cam chain chamber 2c as viewed in the crankshaft direction. The oil reservoir 86 extends above the oil reservoir 86 provided on the bearing wall 22L, and an oil lock tensioner lifter 83 is connected to the oil reservoir 86.
Therefore, oil is effectively supplied to the oil reservoir 86 by the oil guide rib 29 protruding from the left bearing wall 22L facing the cam chain chamber 2c, thereby preventing the oil lock type tensioner lifter 83 from deficient in oil. Thus, the function of the tensioner roller 82 is ensured, and the effect of suppressing the swing of the cam chain 54 by the guide roller 55 is ensured.

Although one embodiment of the present invention has been described above, the aspect of the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention includes those implemented in various aspects within the scope of the gist of the present invention. For example, the internal combustion engine is not limited to that of the embodiment, and the vehicle is not limited to a motorcycle, and includes a three-wheeled, four-wheeled buggy and the like.
For convenience of explanation, the internal combustion engine has been specifically described as having the left and right arrangements shown in the embodiments, but those having different left and right arrangements are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crankcase, 2a ... Outer wall, 2c ... Cam chain chamber, 2L ... Left crankcase, 2R ... Right crankcase, 3 ... Transmission, 4 ... Cylinder block, 4a ... Outer wall, 4c ... Cam chain Chamber, 5 ... cylinder head, 5c ... cam chain chamber, 6 ... cylinder head cover, 7L ... left case cover, 8 ... cam chain tensioner device, 10 ... AC generator, 20 ... crank chamber, 21 ... crankshaft, 21a ... shaft center , 21L ... left crankshaft, 22L ... left bearing wall, 24 ... peripheral wall, 25 ... circular opening, 25a ... opening center, 25b ... inner edge, 26 ... separator member, 28A ... one boss, 29 ... oil guide rib, 51 ... cam shaft, 51a ... shaft center, 53 ... driven sprocket, 53c ... rotation center, 54 ... cam chain, 54p ... pin center, 55 ... guide roller, 55c ... rotation center, 56 ... sub guide roller 57 ... guide roller shaft, 57a ... shaft center, 58 ... sub guide roller shaft, 58a ... shaft center, 30 ... drive sprocket, 80 ... tensioner arm, 82 ... tensioner roller, 83 ... oil lock tensioner lifter, 84 ... push rod 86: Oil reservoir, P: Virtual plane perpendicular to camshaft 51 including driven sprocket 53, r53: Radial distance, r55: Radial distance, d1: Interaxial distance, d2: Interaxial distance

Claims (5)

A driven sprocket (53) that receives the rotational force from the crankshaft (21) via an endless annular cam chain (54) and rotates the camshaft (51) pivotally supported by the cylinder head (5), and a cylinder block (4) A guide roller (55) pivotally supported within the cam chain (54) for guiding the cam chain (54) on the inner peripheral side of the cam chain (54), and the crankshaft (21) side of the guide roller (55). Thus, a cam chain tensioner device (8) for pressing the cam chain (54) from the outer peripheral side of the cam chain (54) by a tensioner roller (82) and applying tension to the cam chain (54), and the cam chain ( 54) In the cam chain guide structure of the internal combustion engine (1) provided with a sub guide roller (56) for guiding the tension roller (82) together with the tensioner roller (82) from the outer peripheral side.
Said guide roller (55) Ri same diameter der and the driven sprocket (53),
The cam chain guide structure for an internal combustion engine , wherein at least a part of the guide roller (55) protrudes from an upper end surface of the cylinder block (4) and is positioned in the cylinder head (5) .   A driven sprocket (53) that receives the rotational force from the crankshaft (21) via an endless annular cam chain (54) and rotates the camshaft (51) pivotally supported by the cylinder head (5), and a cylinder block (4) A guide roller (55) pivotally supported within the cam chain (54) for guiding the cam chain (54) on the inner peripheral side of the cam chain (54), and the crankshaft (21) side of the guide roller (55). Thus, a cam chain tensioner device (8) for pressing the cam chain (54) from the outer peripheral side of the cam chain (54) by a tensioner roller (82) and applying tension to the cam chain (54), and the cam chain ( 54) In the cam chain guide structure of the internal combustion engine (1) provided with a sub guide roller (56) for guiding the tension roller (82) together with the tensioner roller (82) from the outer peripheral side.
  The guide roller (55) has the same diameter as the driven sprocket (53),
  The cam shaft (51) in a side view of the cam chain chamber (5c, 4c) in which the cam chain (54) is disposed from the upper end surface of the cylinder head (5) to the lower end surface of the cylinder block (4). The front and back surfaces of a virtual straight line connecting the shaft center (51a) of the guide roller (55) and the shaft center (57a) of the guide roller shaft (57) of the guide roller (55) are continuous along the virtual straight line direction. A cam chain guide structure for an internal combustion engine, comprising: The distance (d1) between the shaft center (51a) of the cam shaft (51) and the shaft center (57a) of the guide roller shaft (57) of the guide roller (55), and the guide roller shaft (57) claim 1 or claim, wherein the center distance between the axis to the center (58a) and (d2) is equal the axis center from said (57a) sub-guide rollers sub guide roller axis (56) (58) 3. A cam chain guide structure for an internal combustion engine according to 2 . The cam chain tensioner device (8) has an oil lock type tensioner lifter (83) provided on the bearing wall (22L) of the crankcase (2) and having a push rod (84) inserted therein.
The tensioner roller (82) is pivotally supported by a tensioner arm (80) that is pressed and swung by the push rod (84).
The crankcase (2) is provided with an oil guide rib (29) protruding from the bearing wall (22L) facing the cam chain chamber (2c) of the crankcase (2). ) Extends to above the oil reservoir (86) provided in the bearing wall (22L) facing the cam chain chamber (2c) when viewed in the crankshaft direction,
In the oil reservoir (86), the oil lock tensioner lifter (83), characterized in that is connected claims 1 to cam chain of any internal combustion engine according to one of claims 3 Guide Construction.   The cam chain (54) positioned in front of the cam shaft (51) and above the contact point with the guide roller (55), and rear of the cam shaft (51) and the guide roller (55). The cam chain (54) located above the contact point is substantially parallel in a side view,
At least a part of the cam chain (54) positioned forward and downward with respect to the guide roller (55) and at least a part of the cam chain (54) positioned rearward and downward with respect to the guide roller (55) The cam chain guide structure for an internal combustion engine according to claim 1 or 2, wherein the cam chain guide structure is inclined in a direction in which lower portions approach each other in a side view.

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